Water-insoluble bacteriostats in soap and detergent solutions



United States Patent 3 431,207 WATER-INSOLUBLE BACTERIOSTATS IN SOAP ANDDETERGENT SOLUTIONS Kenneth L. Russell, Nutley, N.J., assignor toMalmstrom fhemical Corp., Linden, N.J., a corporation of New ersey N0Drawing. Filed June 28, 1965, Ser. No. 467,693 U.S. Cl. 252-106 3 ClaimsInt. Cl. Clld 3/48 This invention relates to aqueous compositionssuitable for use as shampoos, skin cleansers, and for like purposes, andis particularly concerned with the production of compositions of thischaracter having normally waterinsoluble bacteriostatic agentsincorporated therein.

In recent years, a number of efiorts have been made to impartantibacterial and antifungal properties to shampoos and other skincleansing products. As a result of those eiforts, numerous varieties ofantibacterial liquid cleansers, soaps and detergent bars, as well as ofanti-dandruli shampoos have appeared on the market.

These known products derive their claimed antibacterial properties fromthe incorporation therein of antibacterial agents which are poorly oronly slightly Watersoluble. Some of the slightly water-solubleantibacterial agents employed in these products may be quite readilysolubilized in significant concentrations in fatty acid soap or anionicsynthetic detergent solutions, usually with the aid of heat.Illustrative of these latter antibacterial agents is 2,2-methylenebis[3,4,6-trichlorophenol] commonly referred to as hexachlorop'hene, acommercial variety of which is sold under the trademark G-ll. Alsoillustrative of the aforesaid agents is bis(2-hydroxy-5-chloro-phenyhsulfide, a commercial variety of which, known by thedesignation S-7.

Other antibacterial agents employed in the above-mentioned products are,however, not adequately solubilizable in soap or anionic syntheticdetergent solutions as aforesaid, but require the use of added chemicalsand rather careful techniques in order to solubilize them in significantamounts, even in soap or other anionic detergent solutions.

Illustrative of such practically water-insoluble antibacterial agentsare: (a) 3,4,4'-trichloroca-rbanilide, commonly referred to as TCC; and(b) a mixture of 5,4- dibromosalicylanilide and3,5,4-tribromosalyicylanilide, a commercial variety of which is soldunder the trademark Diaphene.

By reason of their being practically water-insoluble and of theconsequent difliculties of solubilizing significant amounts thereof insoap or other anionic detergent solutions, the use of theseantibacterial agents has been essentially confined to the opaque typesof liquid cleansers, shampoos and the like, since they may remainsuspended in their insoluble state in such products without affectingthe opaque appearance of the products.

The principal object of the present invention is to provide aqueouscompositions suitable for use as shampoos, skin cleansers and the like,having incorporated therein effective amounts of a bacteriostat of thetype which is normally practically insoluble in water and solu ble onlywith difficulty in soap or other anionic detergents, but which isrendered soluble in aqueous solutions of soap and synthetic detergents,whether of the anionic or amphoteric variety, constituting the base ofthe shampoo, skin cleanser or like aqueous composition.

Another object of the invention is to provide aqueous compositions asaforesaid, wherein the agent employed for solubilizing such bacteriostatis one which exerts substantially no effect upon the antibacterialactivity of the bacteriostat.

Still another object of the invention is to provide aqueous compositionsas aforesaid, and containing lanolin oil, in addition to effectiveamounts of such bacteriostat.

A further object of the invention is to provide aqueous compositions asaforesaid, containing effective amounts of such bacteriostats and asuitable quantity of lanolin oil, and wherein the agent employed forsolubilizing the bacteriostat serves also to render the lanolin oilsoluble in the aqueous solution of the detergent, thereby makingpossible the production of clear and transparent liquid shampoos and thelike, containing such bacteriostats as well as lanolin.

The foregoing and other objects of invention and the advantages thereofwill be more specifically apparent from the detailed description whichfollows herebelow.

Stated generally, the objects of the invention may be achieved bypreparing an aqueous shampoo, skin cleanser, or like composition,utilizing soaps or known synthetic detergents as the base, andincorporating therein a bacteriostat of the aforesaid water-insolubletype, solubilized in the aqueous base by means of a non-ionic organicmaterial comprising particularly a polyethoxylated compound selectedfrom the group consisting of polyethoxylated lanolin alcohol,polyethoxylated fatty acid salts of sorbitan, as for example, sorbitanmono-oleate, and polyethoxylated phenols, as for example, nonyl phenol.M More specifically, the bacteriostat employed in the practice of theinvention may be a polyhalocarbanilide, as exemplified by the TCCreferred to above, or polyhalosalicylanilides or suitable mixtures ofthe latter as exemplified by the Diaphene product also referred toabove.

The polyethoxylated compounds employed as solubilizer for thebacteriostat in the practice of the invention have been found to servethe purposes hereof when present in amounts of from about 2% to about5%, preferably 4%, by weight of the composition, the higher amountsbeing particularly advantageous when the composition contains lanolinoil in addition to the bacteriostat, in which event the solubilizerserves, dually, to solubilize the lanolin oil in the aqueous soap ordetergent solution constituting the base of the composition.

In the following table, there are shown the formulations of four typicalsoap or detergent base solutions which may be treated in accordance withthe invention for the product-ion of shampoos or skin cleansers havingantibacterial properties.

TABLE I.-COMPOSITION OF DETERGENT SOLUTIONS Amount in Grams A B C DConcentrated Liquid Soap (36%).. Diethanolamicle of coconut fatty acDeiouized water The aqueous solutions of the detergents shown in Table Imay be made up as stock solutions, for use in the preparation ofcompositions containing the practically water-insoluble bacteriostats.

Thus, for example, 90 gram portions of these solutions may be utilizedto prepare 100 grams of the bacteriostatcontaining product.

The maximum percentage of the bacteriostat which may be solubilized inthe aqueous detergent solution may conveniently be determined by trialand observation, as in the following manner: one gram of thebacteriostat, weighed on an analytical balance to the nearest milligram,is added to 4.0 grams of the polyethoxylated nonionic material, weighedto the nearest one-tenth gram in a 30 milliliter beaker. The mixture isheated at 75 to 80 C., until the bacteriostat is dissolved. Ifoccasionally a slightly higher temperature is required to hastensolution of the bacteriostat, the solution is then permitted to returnto a temperature of 7580 C. 90 grams of the detergent solution isweighed into a 150 milliliter beaker and 5.0 grams of deionized water isadded, both these being weighed to the nearest one-tenth gram. Thisdetergent solution is heated to 75-80 C., whereupon the solution of thebacteriostat in the non-ionic material is added at that temperature tothe detergent solu-ion with stirring. The 30 milliliter beaker in whichthe bacteriostat was dissolved in the non-ionic material is washed withthe detergent solution to assure that all of the non-ionic materialhaving the bacteriostat in solution therein is contained in the product.The latter is allowed to stand until it cools to around roomtemperature, and is then again weighed and sufiicient water added toreplace any water that may have been lost by evaporation, so that thetotal weight of the product is 100.0 grams. The product is then bottledfor observation during varying periods of aging thereof.

In the case of the two typical water-insoluble bacteriostats mentionedabove, viz, TCC and Diaphene, tests were conducted to determine theamounts thereof, respectively, that could be solubilized by each of thethree polyethoxylated non-ionic compounds mentioned above, viz,polyethoxylated lanolin alcohol, a polyethoxylated sorbitan monooleate(Tween) 80) and polyethoxylated nonyl phenol (Igepal CO-630) in each ofthe four above-mentioned detergent solutions. In each instance, theamount of the polyethoxylated compound employed was 4% by weight of thetotal composition. In Table II herebelow, are set forth the data withrespect to the maximum percentage of the respective bacteriostats whichwere solubilized in this manner. These maximum percentage figures setforth in Table II represent the percentages of the bacteriostatssolubilized in the various aqueous detergent systems therein shown, tothe extent that the solutions remained clear during a period of agingfor at least one month. It will be understood, nevertheless, that whenusing the non-ionic solubilizing agents in amounts less than theabove-stated 4% by weight of the composition, the resultant product maybe clear when first prepared, but that precipitation of the bacteriostatmay occur after a period of aging at room temperature, the aging periodvarying from overnight to as long as perhaps one month after preparationof the composition.

In accordance with the invention, it has further been found thatdetergent solutions containing the normally water-insolublebacteriostats solubilized as stated above and as set forth in Table IImay also be made to contain liquid lanolin oil as an ingredient thereof.To that end, the lanolin oil may be incorporated in the mixture of thepolyethoxylated nonionic material and bacteriostat, and then combiningthat mixture with the aqueous solution of the detergent, in the mannerabove described, without otherwise altering the procedure for producingthe desired composition. Thus, referring to the abovedescribedprocedure, one gram of lanolin oil, replacing one gram of water may bethus utilized, to provide a composition containing about 1.0% to about3% by weight of the lanolin oil. With this percentage of lanolin oil, itappeared that by the procedure described above, only the polyethoxylatedlanolin alcohol served effectively to solubilize both the bacteriostatand the lanolin oil, and then only in the detergent solutions made withthe single synthetic detergents (i.e., detergents A and B, supra) andnot in the case of the soap solution or the solution of mixed syntheticdetergents (i.e., detergents C and D, supra). In the case of detergentsolutions A and B, however, it was found that with the polyethoxylatedlanolin alcohol, namely, polyoxyethylene lanolin alcohol condensed with16 mols of ethylene oxide, the presence of the lanolin oil surprisinglybrought about an increase in the amount of bacteriostat which could besolubilized. Thus, compared to the 1.0% of Diaphene and 0.2% of TCCsolubilized in detergent A by the Nimcolan S in the absence of lanolinoil, the respective amounts thereof solubilized in the presence thereofby the Nimcolan S in detergent A were 1.2% and 0.3%. Similarly, whereasthe Nimcolan S served to solubilize 0.6% of Diaphene and 0.1% of TCC indetergent B in the absence of lanolin oil, it served to solubilize 0.7%and 0.3% of the Diaphene and the TCC, respectively, in the presence of1.0% of lanolin oil. Here again, the percentages stated for the amountof the respective bacteriostats solubilized by the Nimcolan S in thepresent of the 1.0% of the lanolin oil represents concentrations whichremained stable during an aging period of at least one month at roomtemperature.

Although no extensive tests have been made with respect to thebacteriological properties of the above-described compositions, suchtests were made on those of the products above set forth whereintriethanolamine lauryl sulfate constituted the detergent (detergent A,supra). Accordingly, Table III sets forth the compositions of a numberof samples subjected to bacteriological testing as hereinafter setforth. In Table III, samples designated Nos. 1 to 8, inclusive,represent compositions embodying the invention. As indicated above,bacteriostats such as hexachlorophene, although only slightly soluble inwater, may be solubilized in anionic synthetic detergent solutions.Samples designated 9 and 10 in Table III are compositions containing 1%of hexachlorophene in the presence and in the absence, respectively, ofa nonionic polyethoxylated solubilizer (namely, Nimcolan S), sample 9having been prepared under conditions the same as those used for theinsoluble bacteriostats of samples 1 to 8, inclusive, and sample 10having been made by TABLE II.-MAXIMUM PERCENTAGE OF BACTERIOSTATSOLUBILIZED TEA Lauryl TEA Dodecyl Mixed K. Coco Soap Sulfate BenzeneDetergent C Detergent D Nonionic Detergent A Detergent B Diaphene TC 0Diaphene TCC Diaphene TC 0 Diaphene TOO Nimcolan S 1 1. 0 0. 2 0. 0 0. 10. 4 0. 1 0.7 0.2 Tween 0.9 0.2 1.0 0.5 1. 7 0. 4 0. 8 0.2 Igepal 00-6300. 9 0. 3 0. 7 0. 2 0. 9 0. 3 0. 8 0. 2

l Trademark for a polyoxyethylene ether of lanolin alcohol with 16 molsEth O.

heating the hexachlorophene with the other ingredients at 75-80 C. TableIII is as follows:

TABLE III.PERCENTAGE COMPOSITIONS OF SAMPLES FOR BACTERIOLO GY TESTINGSample No. 1 2 3 4 5 7 8 9 10 11 12 13 14 15 16 TEA Lauryl Sulfate 20 2020 20 20 20 20 20 20 20 20 20 20 20 20 Schercomide S00 Extra-.. 3 3 3 83 3 3 3 3 3 3 3 3 3 3 Nimcolan S 4 4 4 4 Tween 80 4 4 Igepal 00-630. 4

Diaphene 1. 2

Lantrol l 1. 0 1. 0

HexachlorophenepH of Samples l Trademark for a liquid lanolin oil.

Although soap and detergent solutions have been known to possessantibacterial properties, and have been utilized as carriers for morepowerful antibacterial agents, it is also known that under manyconditions the soaps or detergents in fact reduce the bactericidalaction of the antibacterials (M. E. L. McBain and E. Huchison,Solubilization 199-203, Academic Press, New York, N.Y., 1955).

There is also extensive literature dealing with the interference ofpolyethoxylated nonionic surfactants with cosmetic preservatives,particularly phenolics.

Accordingly, in organizing the procedure for the bacteriological testshereinafter referred to, they were conducted so as to determine whetheror not the polyethoxylated nonionic solubilizers for the normallyinsoluble bacteriostats employed in accordance with the invention wouldhave an additional effect upon the activity of the bacteriostats. Asalready indicated above, in the absence of these nonionicpolyethoxylated compounds as solubilizers for the bacteriostats, thelatter can exist in the aqueous solutions of the detergents only insuspended form, or at best only slightly solubilized therein. With theforegoing in view, the compositions of samples 12 to 16, inclusive, wereprepared in order to compare as accurately as possible theirantibacterial activities with those of the compositions represented bysamples 1 to 8, inclusive, containing the normally water-insolublebacteriostats solu bilized in the aqueous detergent solutions inaccordance with the invention. In the preparation of the compositions ofsamples 12 to 16, inclusive, the bacteriostat was heated with the otheringredients for a few minutes at 75-80 C. and the mixture then allowedto cool. After adjusting for lost water, the sample was then treatedwith a mortar and pestle to grind the suspended bacteriostat to asmaller particle size in order to decrease its settling rate.

The composition represented by sample 11 of Table III, and containingonly the triethanolamine lauryl sulfate and the diethanolamide ofcoconut fatty acids (Schercomide SCO Extra) was prepared by heating theingredients together, again bringing the temperature to 75-80 C. Thissample 11 served, accordingly, as the control sample in thebacteriological tests.

The bacteriological tests and the data obtained as a result thereof wereconducted by the laboratories of two separate suppliers ofbacteriostats, and by one commercial testing laboratory.

The tests to determine bacteriostatic activity were conducted by atwo-fold agar dilution technique. Stock solutions of each formulationwere made in sterile distilled water to give a 20% solution (v./v.).Two-fold serial dilutions with sterile distilled water were thenprepared in x 150 mm. culture tubes such that the final volume of eachtube in the dilution series was 1.0 ml. 24 ml. of 48 degree molten,sterile dextrose tryptone extract agar were then added to each tube inthe dilution series, and the mixture immediately poured into sterilepetri plates (1.00 mm.). Hardened agar plates were surface-streaked with0.01 ml. of a 1-100 water dilution of Escherichia coli andStaphylococcus aureus. Twenty-four hour C., Asso- 1.0 (7Dgilonized Water(1.5 in all samples) nocula. Samples were all tested simultaneously onthe same day. As a result of the foregoing tests, it was observed thatnone of the samples inhibited growth E. coli at a product dilution of1:125. In the case of S. aureus, however, the dilutions at which growththereof is completely inhibited at the end of 48 hours incubation at 35C., are shown in the following table.

TABLE IV.INHIBITING DILUTION, AGAR PLATES, S. AUREUS P.p.m.

Sample No. Bacterlostat Solubilizer Inhibitory Bacte- Dilutlon riostat 11.0% Diaphene.... NS 18,000 1.25 2 0.9% Diaphene.-.- Tw. 1-8, 000 1.11do. I 1. 11 0. 25 0. 25 0. 18 l. 50 0.37 1. 25 1. 25

12 1.0% Diaphene d0 1-8,000 1 25 13. 0.9% Diaphene d0 18,000 1. 11 141.2% Diaphene.. l. 50 15- 0.3% T00" .37 ML 0.3% TCC .25

1 NS=Nin1colan S, Tw=Tween 80, Ig=Igepal 00-630, NS(+L)= Nimcolan S and1.0% Lantrol.

The undiluted samples, supra, were also tested to determine their phenolcoeflicients. These tests were made according to the phenol coefficientprocedure given in Methods of Analysis of the Association of OfficialAgricultural Chemists, 9th edition, pp. 63-65. The test organism usedwas Staphylococcus aureus ATCC No. 6538. The subculture medium wasLetheen broth.

After an incubation period of 24 hours, all culture tubes from samplescontaining TCC and those containing hexachlorophene showed growth. Therewas little or no growth, however, after such incubation, in the tubescontaining Diaphene. One ml. of sterile horse serum was added to all thetubes prepared from the samples containing Diaphene. After incubatingfor an additional 24 hours, all tubes showed growth of the testorganisms.

The phenol resistance of the test innoculum was determined in accordancewith the above-mentioned procedure, a 1:60 dilution killing in tenminutes but not in five, and a 1:70 dilution killing in fifteen but notin ten. According to this test, none of the 16 samples tested killed aninnoculum of S. aureus in a fifteen-minute exposure at 20 C.

Tests to determine the bacteriostatic and bactericidial activity of thecompositions in nutrient broths were made by preparing dilutions of thetest samples in distilled water. Initial dilutions of 1:100 were madewith all of the samples. Subsequent dilutions were made, where required,so as to contain ten times the highest concentration of the activematerial to be tested. Three serial two-fold dilutions were made of thesolutions. The active material concentrations of these 10X solutionswere 20.0, 10.0, 5.0 and 2.5 ppm. for tests of samples 1, 2, 3, 7, 12,13 and 14, which contained Diaphene. In the case of samples 4, 5, 6, 8,15 and 16, which contained TCC, the solutions contained 15.0, 7.5, 3.75and 1.8 ppm. Samples 9 and 10, which contained hexachlorophene, wereprepared at concentrations of 10.0, 5.0, 2.50 and 1.25 p.p.m.hexachlorophene. Sample 11 (the detergent control) was diluted so as toprovide detergent concentrations in the broth tubes equivalent to thatpresent in the test of the samples containing the bacteriostats. Thus,the concentrations of the dilutions in the case of sample 11 were 750ppm. to 23.4 ppm. by two-fold increments, sample 11 being considered100% active in calculating these dilutions.

In preparing the dilutions of samples 12 to 16, inclusive, whichcontained the bacteriostats but without the solubilizer of the presentinvention, and hence having the bacteriostats only in suspended form inthe aqueous mediurn, or at best only slightly solubilized in thedetergent solutions, care was taken to insure that the bacteriostaticmaterial under test was thoroughly dispersed in the aqueous medium byshaking the test material before withdrawal of each aliquot.

The broth culture medium utilized in these tests was prepared accordingto the formula specified for germicide testing in Methods of Analysis ofthe Association of Official Agricultural Chemists, 9th edition,paragraph 5.001 (a) (l). The specified Armour peptone was replaced byBacto-Peptemin, a USP peptone. The broth was tubed in 8.9 ml. amounts,capped with aluminum caps, and sterilized by autoclaving at 121 C. for20 minutes. One-ml. amounts of each sample dilution were added to eachof four tubes of broth. Three of these were each innoculated with 0.1ml. of a 24-hour nutrient broth culture of 3O Staphylococcus aureus ATCCNo. 6538. The fourth tube was not inoculated and served as a samplesterility control as well as a sample turbidity control.

Two sets of four culture controls were prepared. For

these, one ml. of water was added to each tube in each set. Theuninoculated tube from one set of these culture control tubes wasutilized as a reference tube for standardizing a Coleman Juniorspectrotometer. The instrument was standardized at 80% transmittance ata wave length of 580 millimicrons. The transmittance of each of each ofthe tubes containing the various test dilutions was determinedimmediately after the addition of the inoculum. The tubes prepared fromsamples 12 to 16, inclusive, were shaken continually from the time ofthe addition of the test dilution until removal from the incubator. Thetubes were removed individually from the shaker, in order to determinetransmittance. All of the tubes were incubated for 24 hours at 37 C. andtransmittances were then re-determined. One set of the culture controltubes was shaken during incubation, and the other set was not shaken.

In order to determine more precisely the minimal amounts of growth inthe culture tubes and to detect any decrease in the innoculum during the24-hour exposure of the inoculum to the test materials in broth, platecounts were made of all tubes showing little or no change in turbidityduring incubation. After making the final transmittance readings, thethree incubated tubes in each set were cooled and appropriate aliquotswere plated with trypticase soya agar (BBL). The plates were incubatedfor 24 hours at 37 C. and the developed colonies were counted. Thepopulation of the original inoculum was determined by plate count at thetime of inoculation of the culture tubes. Plate counts were also made ofthe culture control tubes and the detergent control tubes (sample 11).

The results of the bacteriological tests above described are summarizedin the following Tables V and VI.

P.p.m. of Active Amount of Growth None Slight Moderate UnlnhibitedSolubilizer 1 Sample:

1 0.5 Diaphene NS X 0.25 Diapheue NS 2 0.5 Diaphene Tw X 0.25 DiapheneTw X 3 1.0 D e Ig X 0.5 Dlaphene Ig-.. X 0.25 Diaphene Ig X 4 1.5 TOG NSX 0.75 TCC. N X 0375 T NS X 0.18 TOO" NS 5 1 5 TOO Tw 0.75 TCC- 0.375'ICC- 0.18 TCC-- 6 0.18 'ICC Tr! X 7 0.5 Diaphene NS(+L) X 0.25 DiapheneNS(+L) 8 0.375 'ICC NS(+L X 0.18 TOO--- NS(+L) 9 0.5 G-11 NS X 0.25 G-llNS 0.125 G-11 NS 10 1.0 G-ll Nnna X 0.5 G-ll (in X 0 G" an X 0 G-11 do X11 (Control) 750 Product Basis 375 Product: Basis X 187.5 Product Basis"X 93.8 Product Basis"--. X 47 Product Basis X 28.5 Product Basis X 122.0 Dlanhann Nnnn X 10 Dianhano fin X 0.5 Din'nhane do X 13 2.0 DirmhaneNona X 1,0 Dirmhann do X 0,5 Dinphmm do X TABLE VCon'tin'ued' Amount ofGrowth P.p.m. of Active Solubilizer 1 None Slight Moderate Uninhiblted14 2.0 Diaphene Nmm X 1,0 Dianhann do x 15 1.50 TCC- None X 0.375 TOO doX 16 20.0 TCC N X l NS=Nimcolau S, Tw=Tween 80, Ig=Igepal -630,NS(+L)=Ni.meo1an S and 1.0% Lantrol.

TABLE VI.PERCENT DECREASE IN POPULATION, NUTRIENT BROTH, S. AUREUS, 24HOURS P.p.m. of Diaphene Solubillzer 1 P.p.m. of TCC P.p.m. ofHexaehlorophene 9 (NS 10 None .8%

NS=Nimoolan Tw=Tween 80, Ig=Igepa1 00-630, NS(+L)= s Nimeolan s and 1.0%

lncrease.

In evaluating the tests referred to above, on the 'basis of thetubridinetric changes only, net transmittance changes up to 10% 0f thechange in the culture control are considered to indicate completeinhibition of growth. Changes in net transmittance over 50% of that ofthe culture control tubes are considered to indicate too littleinhibitory activity to have any practical significance. These nettransmittance changes are arrived at by determining the average decreasein transmittance of the three innoculated tubes of each set andcorrecting this figure by subtracting any decrease in transmittance ofthe sample control or by adding any increase in transmittance of thesample control. Degrees of inhibition of growth as indicated by thechanges in transmittances are shown in Table V, above. Decreases in theinitial population present in the culture tubes containing variousconcentrations of the test materials as determined by plate counts areshown in Table VI, above.

Lantrol.

In addition to the foregoing tests, calf skin substantivity tests werealso conducted. For the purposes of the last-named test, fresh calf skinwas obtained from the flang area before any curing procedure such assalting or pickling had been undertaken. The skin was prepared for thetest by shaving off the epidermis, and defleshing the flesh side, Theshaving operation involved the use of no soap or other shavingassistants. In performing this test, the original samples were dilutedbefore testing to provide a concentration of 0.1% bacteriostat in each.The control sample, i.e., sample 11, was diluted 1: 10. The shaved skinsamples were placed on glass plates and the diluted composition to betested was applied to the epidermis side, massaging it into the skinlightly for a period of ten seconds. After this massaging, the samplewas allowed to remain on the skin for a period of one minute, afterwhich it was removed first by wiping and then by rinsing in cold, clearWater. The rinsing was performed by allowing clear, cool water to passover the skin pieces after treatment with the samples, in a runningwater bath for thirty seconds. In Table VII herebelow, showing theresults of the calf skin substantivity tests, the figures for two andfour rinses have reference to removal of the test pieces, allowing themto drip for one minute, and then reimmersing them.

Test pieces 12 mm. in diameter were removed from the skins by use of acork borer of the appropriate size. Test pieces were taken after 1, 2and 4 rinsings as described above. Three pieces from each rinsing periodwere placed on nutrient agar plates seeded with Staphylococcus aureusfrom a 24-hour old culture, with the epidermis side in contact with theagar. After incubation for 24 hours at 37 C., the results were read aszones of inhibition in millimeters, Other test pieces, taken after twoand four rinsings, were held in a room temperature-% relative humiditychamber for periods of 24 hours and 72 hours before placing them on theseeded agar plates for determination of the zone of inhibition. Alltests were performed in triplicate and all readings are based on theaverage of these three readings to the nearest 0.5 mm. The results areshown in the following table.

TABLE VII.-CALF SKIN SUBSTANTIVITY, ZONES OF INHIBITION (1mm), S. AUREUSNo Aging 24 hours, R.'I., 72 hours, R.T., Bacteriostat slpzlub i- 85%R.H. 85% R.H.

1 n'nse 2 rinses 3 rinses 2 rinses 4 rinses 2 rinses 4 rinses Sam 1e No.

I Dlaphene--. NS 10. 5 8. 5 8. 0 8. 0 8. 0 8. 0 8. 0 d T 8.0 8.0 8.0 8.08.0 8.0 8.0 10. 0 8. 5 8. 0 8. 0 8. 0 8. 0 8. 0 7.0 4.0 3.0 0.0 0.0 0.00.0 8. 0 4. 0 3. 0 0. 0 0. 0 0. 0 0. 0 10. 0 4. 0 3. 0 0. 0 0. 0 0. 0 0.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 7.5 4.5 3.0 0.0 0.0 0.0 0.0 6.5 5.0 8.00.0 0.0 0.0 0.0 6.5 5.0 8.0 0.0 0.0 0.0 0.0 2.0 0.0 0.0 0.0 0.0 0.0 0.012 Diaphene .-d0 5. 5 5. 0 5. 0 5. 0 5. 0 5. 0 5. 0 13 do o 6.0 5.5 5.55.0 5.0 5.0 5.0 7.0 5.5 5.5 5.5 5.0 5.0 5.0 5.5 4.0 2.5 0.0 0.0 0.0 0.06.0 4.0 3.0 0.0 0.0 0.0 0.0

I All samples diluted to 0.1% concentration of bacteriostat beforetesting. Sample 11 diluted 1:10.

for meaning of abbreviations.

1 See Tables IV, V and VI From the foregoing description, it will beapparent to those skilled in the art that While the invention hereof hasbeen illustrated in embodiments wherein the waterinsoluble bacteriostatsare illustrated by TCC and Diaphene, the objects and advantages of theinvention may be obtained with the use of other such bacteriostats, suchas 2-hydroxy-5-chlorobenzoic acid 3',4-dichloranilide, marketed underthe trademark Anobial.

As is evident from the description, and particularly the data set forthin Table II, a useful percentage of each of the bacteriostats may besolubilized in each of the four typical detergent solutions by the useof any one of the three polyethoxylated compounds herein set forth, asillustrative of nonionic polyethoxylated compounds suitable for thepurposes hereof. As demonstrated by the data hereinabove set forth, eachof the three specific nonionic compounds has been found capable ofeffecting the solubilization of a greater amount of the Diaphene than ofTCC in each of the detergent solutions. It is apparent, therefore, thatthe efficiency of a given nonionic polyethoxylated compound forsolubilizing a given bacteriostat varies somewhat, depending upon thedetergent system utilized as the base of the composition in which thebacteriostat is to be dissolved.

Furthermore, as already pointed out, simultaneous solubilization oflanolin oil in an amount of 1.0 by weight thereof, based on the weightof the total composition, may be achieved when using certain of thedetergent solutions, if the solubilizing agent employed is apolyoxyethylene ether of lanolin alcohol condensed with 16 mols ofethylene oxide, without causing any interference by the lanolin oil withthe solubilization of the bacteriostats, the presence of the lanolin oilindeed serving to increase the amount of the bacteriostat which can besolubilized by the aforementioned polyoxyethylene ether of lanolinalcohol.

Insofar as concerns the bacteriological activity of the compositionshereof, if appears that while the bactericidal action is not sufficientto be measured by a short time killing test, such as the phenolcoefficient test, the bactericidal action is nevertheless readilyapparent at fairly low active ingredient concentrations in a longer termtest, as shown by the data in Table VI. Bacteriostatic action againstStaphylococcus aureus, by both of the test trations of TCC than ofDiaphene or of hexachlorophene,

and none of these three bacteriostats shows bacteriostatic actionagainst E. call at sample dilutions of 1:125.

Moreover, as is shown by the data hereinabove set forth, the presence ofthe nonionic polyethoxylated compounds used as solubilizers for thebacteriostat in accordance with the present invention does not appear toreduce the antibacterial action of the active ingredients.

What is claimed is:

1. A shampoo composition consisting essentially of an aqueous solutionof a water-soluble synthetic organic detergent, said detergentconstituting from about 10% to about 30% by weight of the composition,lanolin oil in an amount of from about 1% to about 3% of thecomposition, a water-insoluble bacteriostat constituting from about 0.3%to about 1.5% by weight of the composition and being selected from thegroup consisting of 3,4,4 trichlorocarbanalide, a mixture of 5,4dibromosalicylanilide with 3,5,4 tribromosalicylanilide, 2-hydroxy-S-chlorobenzoic acid, and 3',4 dichloranilide, and a solubilizerfor said bacteriostat, said solubilizer consisting of approximately 2%to 5% by weight of a nonionic polyethoxylated compound selected from thegroup consisting of polyethoxylated lanolin alcohol, polyethoxylatedsorbitan mono-oleate and polyethoxylated nonyl phenol, said amount ofsaid polyethoxylated compound serving also to render said lanolin oilsoluble in said aqueous solution of the detergent.

2. A shampoo composition as defined in claim 1, wherein said solubilizerconsists of a polyoxyethylene ether of lanolin alcohol condensed with 16mols of ethylene oxide.

3. A shampoo composition as defined in claim 1, wherein said amount ofsaid lanolin oil does not impair the antibacterial activity of saidbacteriostat.

References Cited UNITED STATES PATENTS 2,904,468 9/1959 Davis et al.252-106 3,118,842 1/1964 Besser 252106 3,152,039 10/1964 Mattson 2521073,156,656 10/1964 Libby 252-106 3,224,976 12/1965 Farrar et al. 252107FOREIGN PATENTS 887,247 1/1962 Great Britain.

LE methods referred to above 1s apparent at lower concen- ON D ROSDOLExammer' W. SCHULZ, Assistant Examiner.

US. Cl. X.R. 252351, 356, 107

1. A SHAMPOO COMPOSITION CONSISTING ESSENTIALLY OF AN AQUEOUS SOLUTIONOF A WATER-SOLUBLE SYNTHETIC ORGANIC DETERGENT SAID DETERGENTCONSTITUTING FROM ABOUT 10% TO ABOUT 30% BY WEIGHT OF THE COMPOSITION ,LANOLIN OIL IN AN AMOUNT OF FROM ABOUT 1% TO ABOUT 3% OF THECOMPOSITION, A WATER-INSOLUBLE BACTERIOSTAT CONSTITUTING FROM ABOUT 0.3%TO ABOUT 1.5% BY WEIGHT OF THE COMPOSITION AND BEING SELECTED FROM THEGROUP CONSISTING OF 3,4,4'' TRICHLOROCARBANALIDE, A MIXTURE OF 5,4''DIBROMOSALICYLANILIDE WITH 3,5,4'' TRIBROMOSALICYLANILIDE,2HYDROXY-5-CHLOROBENZOIC ACID, AND 3'',4 DICHLORANILIDE, AND ASOLUBILIZER FOR SAID BACTERIOSTAT, SAID SOLUBILIZER CONSISTING OFAPPROXIMATELY 2% TO 5% BY WEIGHT OF A NONIONIC POLYETHOXYLATED COMPOUNDSELECTED FROM THE GROUP CONSISTING OF POLYETHOXYLATED LANOLIN ALCOHOL,POLYETHOXYLATED SORBITAN MONO-OLEATE AND POLYETHOXYLATED NONYL PHENOL,SAID AMOUNT OF SAID POLYETHOXYLATED COMPOUND SERVING ALSO TO RENDER SAIDALNOLIN OIL SOLUBLE IN SAID AQUEOUS SOLUTION OF THE DETERGENT.